Recently in a dental treatment, an implant treatment where an artificial tooth is attached to the artificial tooth root that is implanted in a jawbone instead of a lost tooth with an external thread on its outer periphery is prevailing. The artificial tooth root is implanted in the jawbone from which a tooth has been lost and is functional as a base for the artificial tooth to be attached to the tooth root. In an operation for implanting the artificial tooth root, the artificial tooth root is inserted into a hole of the jawbone formed in the same size as that of the artificial tooth root by screw-fitting, and the artificial tooth root is connected to the jawbone by forming a bone around the artificial tooth root. However, if the hole formed in the bone is larger than the artificial tooth root or the bone around the artificial tooth root is osteoporotic, there is a case where connection to the jawbone requires a long period of time or finally the artificial tooth root is not connected to the jawbone firmly.
Further, a connective tissue of a living body cannot be connected directly to the artificial tooth root, and therefore, there is nothing replacing a periodontal membrane and a periodontal ligament for supporting a tooth on the bone and the gingiva. Accordingly, various substances in a mouth enter into a space between the bone and the artificial tooth root, and bacterial infection and resultant inflammation of the gingiva and the bone arise continuously, thereby progressing bone absorption around the implant. As a result, an epithelium (gingiva) grows toward the bottom of the hole formed in the jawbone (down-growth), namely, the gingiva grows so as to intervene between the artificial tooth root and the jawbone, and there is no connection between the artificial tooth root and the jawbone. Furthermore, in the case of fixing the artificial tooth root to the jawbone using a thread, even if the artificial tooth root is fitted to the jawbone without a space therebetween, a fibrous tissue and an inflammatory tissue grow into the thread groove and a bone does not grow at the side of the upper portion of a thread, namely, no adhesion of the bone and the gingiva onto the upper portion of the thread is obtained. Therefore, a marginal closure of the upper portion of the thread does not occur and inflammation around the implant occurs.
In order to solve the above-mentioned problem, in Patent Document 1, there is disclosed an artificial tooth root 100 comprising a columnar insertion portion 101 and a head portion 102 provided on a upper end of the insertion portion 101, wherein at least a part of an outer peripheral surface of the head portion 102 comprises an induction layer 103 having a three-dimensional structure inducing a bone cell and/or an epithelial cell. According to this artificial tooth root 100, by providing the induction layer 103, a gingiva is induced at the upper side of the artificial tooth root 100 so as to cover the artificial tooth root 100, thereby down-growth of the gingiva can be prevented.